Tourniquet

ABSTRACT

A tourniquet for restricting the venous flow of blood is formed by a strip of elastic material having a series of spaced apertures adapted for selective engagement with an upstanding stud for holding the tourniquet tightened around a body member. The apertures are unevenly spaced to compensate for the stretch of the strip so that substantially the same constricting pressure is applied regardless of the size of the body member.

United States Patent Otto N. Glesne 1426 N. 12th, Fort Dodge, Iowa 50501[21] Appl. No. 850,530

[22] Filed Aug. 15, 1969 [45] Patented Dec. 21, 1971 [72] Inventor [54]TOURNIQUET 1 Claim, 3 Drawing Figs.

[52] U.S. Cl 128/327 [51] 1nt.Cl A611: 17/12 [50] Field of Search128/327 [56] References Cited UNITED STATES PATENTS 1,743,452 1/1930Hatch 128/327 2,271,927 2/1942 Saighman 128/327 PrimaryExaminer-Channing L. Pace Attorney-G. A. Ellstad ABSTRACT: A tourniquetfor restricting the venous flow of blood is formed by a strip of elasticmaterial having a series of spaced apertures adapted for selectiveengagement with an upstanding stud for holding the tourniquet tightenedaround a body member. The apertures are unevenly spaced to compensatefor the stretch of the strip so that substantially the same constrictingpressure is applied regardless of the size of the body member.

WWNTED BEEN FIG.

FIG. 2

INVENTOR TOURNIQUET BACKGROUND OF THE INVENTION This invention relatesto constricting devices for medical usages and more particularly it hasreference to a tourniquet which is wrapped and tightened around an armor limp of a person in order to distend the veins, generally thesuperficial but sometimes the deeper veins. This is necessary in orderto facilitate the puncture of the veins with a needle for extracting asample of blood or effecting intravenous injection of desired material.Under prior art practices, various types of tourniquets have been usedsuch, for example, as a piece of rubber tubing or strip which is wrappedaround a body member and tied or held in place with a clamp. Suchdevices, however, have been unsatisfactory since they do notconsistently provide the optimum pressure to produce adequate distensionof the veins to permit easy and accurate insertion of a needle,especially in the hands of relatively unskilled persons. In addition,some of the prior art tourniquets are reliable and cumbersome in use andfrequently cause discomfort to the patient.

SUMMARY OF THE INVENTION An object of the present invention is toprovide a tourniquet of the type described which will, when in use,apply to the arm or limb substantially the same predetermined optimumconstricting pressure regardless of the size of the arm or limb so thatthe veins will be adequately distended to permit accurate and easyinsertion of a needle. Other objects are to provide a tourniquet whichwill be relatively simple in structure yet efficient in operation andconstructed so that it may be quickly and easily applied to or removedfrom a body member.

In accordance with the invention, a tourniquet is formed of a flat stripof elastic plastic material having fastening means such as an upstandingstud secured thereto adjacent to one end thereof. The strip is providedwith a plurality of spaced apertures which extend lengthwise of thestrip from a point spaced from the stud and are adapted for selectiveengagement with the stud for holding the tourniquet in constrictingrelation around a body member. In order to compensate for the greaterstretch of the strip when applied to body members of larger sizes, thespacings between successive apertures increase progressively beginningwith the aperture nearest to the stud. Because of this arrangement ofthe spacings and apertures, the tourniquet will, when in use,consistently provide substantially the same predetermined optimumconstricting pressure, within a small range, so that adequate distensionof the veins is produced regardless of the circumference of the bodymember to which it is applied.

BRIEF DESCRIPTIONOF THE DRAWING FIG. 1 is a plan view of the tourniquetembodying the invention.

FIG. 2 is an edge view thereof.

FIG. 3 is a perspective view showing the relation of the parts when thetourniquet is in use.

DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of theinvention is shown in the drawing wherein 10 indicates a tourniquetwhich is formed of a flat strip of elastic material. Secured to the endportion 11 of the strip is suitable fastening means such as theupstanding metal stud 12. A plurality of spaced apertures 13 are formedin the strip in substantial alignment with the stud 12 and extendinglengthwise of the strip 10 from a point spaced from the stud 12 andthence towards the end portion 14 of the strip. The apertures 13 areadapted to be selectively engaged with the stud 12 to hold the strip 10in tightened encircling relation with a body member. The spacingsbetween successive apertures increase progressively in length beginningwith the aperture which is nearest to the stud 12, for a purpose to bedescribed hereinafter.

In use, the tourniquet is wrapped around a body member with portions ofstrip 10 in side-by-side parallel relation snugly engaging the memberand with an aperture substantially adjacent to the stud 12. With an endof the strip I held in each hand, the strip is tightened by an amountwhich is produced by moving the strip a distance equivalent to about 2or 2% spacings, for example, and then securing the strip in tightenedposition by forcing the adjacent aperture down over the stud 12. Thetourniquet may be quickly released by raising the strip to move theengaged aperture off the stud 12.

The average arterial blood pressure for a adult varies between about100-200 mm. of mercury whereas the average venous pressure for an adultis about l5-25 mm. of mercury. In order to produce adequate distentionof the superficial veins for the easy and accurate insertion of aneedle, the tourniquet should not produce a constricting pressuregreater than about 90 mm. Hg. since such a greater pressure would undulyimpede or stop the arterial flow of blood. The tourniquet must, however,produce a pressure which exceeds the venous pressure and also overcomesthe resistance provided by tissue, such as fat, in the body member towhich it is applied. The optimum pressure produced by a tourniquet forthe adequate distention of the superficial veins to permit easy andaccurate insertion of a needle varies from about 60-90 mm. Hg. for anadult.

For optimum results, the constricting pressure of 60-90 mm. Hg. shouldbe provided consistently whether the tourniquet is applied to a bodymember having a large or small circumference. The predetermined optimumconstricting pressure on a body member of any size can be obtained bytightening the strip 10 through relative movement of adjacent parts ofthe encircling strip 10 a distance equal to, for example, two or two andone-half spacings between successive apertures 13.

When the tourniquet is applied to and tightened on a large arm, thestrip 10 will be stretched or expanded more than when applied to asmaller arm. Hence, if substantially the same constricting pressure of60-90 mm. Hg. is to be applied to an arm regardless of itscircumference, it is essential that some compensation or allowance bemade for the additional stretch of the strip 10. This is accomplished byspacing the apertures 13 unevenly so that beginning with aperture A,nearest the stud 12, the spacings between successive apertures increaseprogressively. Since the stretch of the material in strip 10substantially varies directly as the force applied, the optimum resultsare provided by making the spacings between successive apertures 13increase by a substantially fixed increment, such, for example, as 0.015inch in the specific embodiment of the invention hereinafter described.Spacings between apertures may be varied depending on the size andmaterial of the strip but it is essential that there be some progressiveincrease in spacing lengths between at least some of the apertures withthe longest spacing being near to the end portion M of the strip.

In one embodiment of the invention which has been made and usedsuccessfully, the tourniquet is formed of a flat extruded strip ofpolyurethane A Durometer. The strip is 24 inches long, 0.656 inches wideand 0.078 inches thick. The upstanding metal stud 12 is located about 4inches from the strip end 11 and the apertures 13 each have a diameterof about 0.156 inches so that they may be forced into releaseableholding engagement with the head on stud 12. The row of apertures 13extends lengthwise of and along the central portion of the strip 10 andin alignment with stud 12. The aperture indicated at A is nearest toand; about 7 inches from the stud 12. The distance between the centersof A and the next aperture B is 0.530 inches; the distance between thecenters of aperture B and the next aperture C is 0.545 inches; thedistance between the aperture C and the next aperture D is 0.560 inchesand so on with the distance between successive apertures increasingprogressively by a substantially constant increment of 0.0 l 5 inches.

In order that the optimum constricting pressure of 60-90 mm. Hg. will beprovided when the tourniquet of the next preceding paragraph istightened around a body member of minimum size with the aperture Aengaged over the stud 12, the elasticity of the plastic strip ismodified by providing eight parallel pairs of holes each having adiameter of 0.109 inches and located between the aperture A and the stud12. Suppose, for example, that the tourniquet is wrapped around a largerbody member so that the strip snugly engages the member and the apertureA is adjacent to the stud 12. Then a tightening of the tourniquet bypulling the ends of the strip so that the aperture C is engaged over thestud 12 will serve to produce the optimum constricting pressure of 60-90mm. Hg. Because of the progressively increasing lengths of the spacesbetween the apertures 13, beginning with the first aperture A, asubstantially constant predetermined pressure, within a range of 60-90mm. Hg., will be provided regardless of the circumference of the bodymember to which the tourniquet is applied. The structural dimensions anddata for the abovedescribed tourniquet were determined experimentallyand resulted in a device which has been very successful in use.

The tourniquet may be made of any suitable elastic material and thestrip may be made in any suitable thickness, width and length. A plasticmaterial such as polyurethane has proven to be highly satisfactorybecause of its resistance to deterioration and consequent retention ofits elastic properties. Whether in the hands of skilled or unskilledtechnicians, the tourniquet of the invention will consistently provide apredetermined optimum constricting pressure on a body member regardlessof its size. The tourniquet is wrapped snugly around a body member withthe end portions of the strip in side-by side relation and, using thestud 12 as a guide, the strip is tightened by pulling the ends of thestrip to move a distance of a substantially fixed number of spaces toconsistently provide the optimum constricting pressure. For thetourniquet which has been described specifically herein, the optimumpressure is provided by tightening the strip by a movement equivalent totwo or two and one half spaces between apertures.

The series of apertures may be serially numbered on the strip 10 tofacilitate the application of the tightening pull by moving the parts acertain fixed number of spaces such as two to two and one half in theexample herein given. The number of spaces to be moved to provide aconsistent predetermined optimum constricting pressure will of course,depend on the dimensions and material of the strip 10 and the spacingsbetween the apertures. For use on a child, the tourniquet would, ofcourse, be appropriately modified in structure. Various modificationsmay be made without departing from the spirit of the invention aspointed out in the appended claims.

I claim:

1. A tourniquet adapted to be placed in encircling relation on a bodymember for restricting the venous flow of blood comprising a strip ofelastic material, fastening means carried by the strip adjacent to afirst end portion thereof, said strip having a plurality of spacedapertures extending lengthwise thereof from a point spaced from thefastening means and thence towards the second end portion of the strip,said apertures being adapted for selective engagement with the fasteningmeans for exerting on a body member a constricting pressure forrestricting the venous flow of blood, the optimum constricting pressurebeing provided when the strip is tightened around a body member with theaperture nearest to the fastening means in engagement therewith, theremaining apertures being unevenly spaced to compensate for the stretchof the strip when it is tightened around body members of larger sizes,the spacings between successive apertures increasing in lengthprogressively by a substantially fixed increment beginning with thespacing nearest to the fastening means whereby substantially the sameoptimum predetermined constricting pressure will be exerted on a bodymember regardless of its circumference.

* t i i

1. A tourniquet adapted to be placed in encircling relation on a bodymember for restricting the venous flow of Blood comprising a strip ofelastic material, fastening means carried by the strip adjacent to afirst end portion thereof, said strip having a plurality of spacedapertures extending lengthwise thereof from a point spaced from thefastening means and thence towards the second end portion of the strip,said apertures being adapted for selective engagement with the fasteningmeans for exerting on a body member a constricting pressure forrestricting the venous flow of blood, the optimum constricting pressurebeing provided when the strip is tightened around a body member with theaperture nearest to the fastening means in engagement therewith, theremaining apertures being unevenly spaced to compensate for the stretchof the strip when it is tightened around body members of larger sizes,the spacings between successive apertures increasing in lengthprogressively by a substantially fixed increment beginning with thespacing nearest to the fastening means whereby substantially the sameoptimum predetermined constricting pressure will be exerted on a bodymember regardless of its circumference.